This disclosure generally relates to assembly of a load compressor for an auxiliary power unit. More particularly, this disclosure relates to fabrication of a load compressor scroll housing for an auxiliary power unit.
Aircraft utilize auxiliary power units for inflight restarting of main engines and to supply compressed air and electric power during ground operations. An auxiliary power unit typically includes a small gas turbine engine that drives a load compressor. The load compressor generates compressed air that can be used for environmental systems and to aid in starting a main engine. A load compressor includes an impeller driven by the small gas turbine engine that generates compressed air guided through a discharge scroll. The scroll is a volute passage defined by the load compressor housing that directs compressed air through a single outlet.
The volute passage is typically formed through known lost wax casting processes. Lost wax casting can be inefficient for some materials and therefore limits the materials utilized for forming the scroll housing.